Marin Downhill Electric Mountain Climber

The goal for my first electric bike project was to have the power to tow my son up the nearby mountains, with a range of 20 miles... all for under $1000US. After spending some time on E-S and learning what was possible, I upped my budget a bit and built a mountain climbing monster!

Before:


After:


Ingredients:

• Marin Downhill donor bike, Full Suspension, 26" wheels
• Crystalyte 5305 (rear)
• 72v40A Crystalyte 4110 controller
• (2) 36v20Ah Headway LiFePO4 packs w/ BMS for a total of 72v20Ah
• Cycle Analyst
• Old Man Mountain Cold Springs Front Rack (50lbs Load Capacity)
• Axiom Seymour Panniers
• Two 3A LiFeP04 chargers

Results:

• Top speed:
  • 36mph, no wind, flat
  • 45.6mph slight downhill
• Range: Depends on terrain...
  • 20 miles including 2000-3000 ft of climbing
  • 16 miles, aggressive, WOT up mountain roads
  • Or up to 50 miles (so far) by riding efficiently
  • 40 miles while towing my son in a double trailer.
• Milestones: Rode 200 miles in the first week
• Total Cost: About $1800 (not including bike)
• Any other stats worth mentioning?

Photos:

Wow!! Looks really good!! Seems like you are really enjoying your new setup, and you have the most beautiful trails and scenery, is the motor performing the way you like? I'm in the middle of moving and will continue my project once I get to AR. Are the batts good, any problems with getting them, how long did it take?

Motor is performing super well. I've ridden it super hard, and had a lot of fun.

That's not to say the project has been without its learning experiences. At first I bought a cheap front rack that made turning impossible, and it ultimately cracked under the weight of the 19lb packs. I'm so thankful I upgraded to the Old Man Mountain rack. Grounding out a pack going 40mph down a mountain is a scary thing. My new pack has loads of clearance, and is much sturdier.

The second challenge has been the slightly taco'd rim from a pinch flat I got the very day I mounted the wheel. I hopped a curb on an under inflated tire and have been riding with a limp ever since. Well this week that's all changing. I have a new rim and tire on its way. I hope to have the wheel built for a couple good rides this weekend.

The build itself wasn't too bad. Not coming with any electronics background was a bit of a challenge, but a few friends and a bunch of E-S folks helped me through the rough spots.

So far I've put 600 miles on the bike in 25 pack cycles. I'm having fun trying to summit all the classic Bay Area rides.

Hi,
I'm doing a similar build: http://endless-sphere.com/forums/viewtopic.php?f=3&t=37358 with 12s1p A123 20ah pouch batteries.

What are you using for a balance and bulk charger? What are you using for a BMS?

Nice build!

Can you show pictures of the front rack? I have a Tora front fork and am thinking about getting one but unsure if I can mount it properly.

thanks!